Description

The goal of this project is to create a bicycle which is smaller, cheaper, and more modular than "regular" bicycles. It can be assembled from a variety of materials and does not require any welding. You can build it in a NYC apartment or an Antarctic research station.

The riding position is relaxed and upright with your hands beside you like when you walk. The pedals connect to the front wheel through gears for maximum compactness.

Make your bicycle yours, build it yourself.

Details

The bicycle is truly a glorious contraption. And an inexpensive commuting vehicle. And a fun toy. And a cargo hauling work tool. And a racing machine. And the next wave of city transportation. And a throwback to a bygone age.

The bicycle has existed for so long, so let’s leave well enough alone, right? No. The bicycle is a great engineering tool. Its inner workings are not covered up. You can prod and poke and see what each component does. This leads the adventurous and inquisitive to make changes. Thousands of garages and basements are full of welders, bent tubes, and homemade bikes.

I decided to invent another kind of bicycle but also to create a system in which people can put together a bicycle from scratch and then have enough knowledge to make some changes. I wanted the bicycle kit to be inexpensive which means using mostly off the shelf parts and staying away from welders, tube benders, ventilation, shop space, and other tools which are out of reach for most people.

The Bellcycle is compact. That’s because the diamond frame on a normal bicycle that separates the two wheels and houses the bottom bracket is gone. The wheels of the Bellcycle can be nearly touching. The cycle cannot get shorter.

The Bellcycle is front wheel drive. The pedal axis is through the front wheel of the bicycle. The user sits in the middle of the bicycle with their hands either in front of them or naturally by their side, depending on your configuration

The Bellcycle currently has both single speed and nine speed versions with standard bicycle chains, sprockets etc. However, in the future a inexpensive hub gear could be designed and produced which would simplify the cycle even further.

The frame is made of tubes connected to plates. In the current version the tubes are 2043 Aluminum and the plates are 6061 aluminum. However, some prototypes have had steel tubes, carbon fiber tubes, and even wood frames. Currently the plates are waterjet cut and holes drilled and tapped for bolts. However, in early prototypes the plates were cut using a bandsaw and hacksaw.

I hope to offer a kit version of the cycle soon which will contain all the parts needed to assemble the cycle.

The CAD is all open source and included in the component and file list.

I have always wanted to build a wooden bike. But I am not really interested in the bamboo bikes or higher end models which use epoxy and composites to join the tubing/spars. I wanted something that was cheap.

One great thing about NYC is there are a lot of people throwing things away. There is always a stack of wood in a dumpster nearby and routinely half mutilated bicycles are in the garbage also.

Wood for the taking. I used the Oriented Strand Board (OSB) leaning up against the building and some of the 2x4's.

I found this jewel in the trash a few months ago. Missing quite a few things but good enough.

The design is similarish to the aluminum bellcycle bikes. It has the front frame which holds the same kind of front drive wheel. The center frame connects to front frame through a headset bearing and has the spring to remove pedal interference. The rear frame freely pivots behind the center frame.

From the trash bike we are going to need

Crankset

Chain

Jockey Wheels

Handlebar Stem

SeatPost

The side pull brake attachment points ( just hacksaw off)

Both wheels, tubes, tires etc.

Headset

The top threaded tube from the fork.

I printed out the shapes of the center frame pieces and laid them out on scrap pieces of wood. Cut them out. Made some poor joinery and glued the whole section together.

I laid out the dimensions of the rear and front frame on the OSB. The OSB was .5 inch and I ended up doubling the width. I cut out and glued together the pieces.

I assembled all the pieces. I used a lot of drywall screws in lieu of glue which I ran out of.

The battery kit includes a slightly noisy rear rack for mounting the battery. The rack was easy to install on the rear dropouts of the bellcycle. I just drilled and tapped two m5 holes into the dropouts and attached the upper mounts to one of the existing bolts on the rear pivot.

The motor kit includes all the wires you will need and they are already plugged in which is a nice time saver. The motor is heavy. I knew this but I forgot just how heavy. I mounted the motor controller under the rear battery rack.

The cycle is fun to ride with the electric motor and that the motor has no problem hurtling you up to speed.

The battery has an impressive range, I have gone 20 miles and gotten home with the orange(but not red) light on and some still in reserve. Of course this is still with a good amount of pedaling.

There is now easily an additional 30 pounds in the rear. I feel it in the responsiveness. The cycle feels a "heavier" and less responsive.

Todo: The electric system is too big and heavy. Pedal Assist would be a better fit. The battery mounting takes up too much room.

One of the benefits of the Bellcycles design is that the rear pivot allows the rear section of the cycle to be easily swapped out and as long as the height of the pivot remains the same, the cycle rides pretty much the same.

So if you are mostly a bicycle commuter but occasionally you need to haul some heavy boxes you could just swap out the rear section of your bike with two bolts and bolt on a cargo back. In this case, I just used a 2x6 piece of wood with an old bmx fork and two small wheels.

The worlds longest bicycle is 117ft says the Guinness Book of Records. Thats not really that long. I could build a light 120 foot beam ( wood? Foam/Fiberglass? Carbon Fiber Tube?) and bolt it on the end.

Where should the rear pivot on the cycle be? From v0.5B when I stuck a office chair caster wheel on the cycle the pivot was very close to the rear wheel. But in later version to simplify the design I moved the pivot towards the front.

The results? Its more maneuverable. You can perform tight tight turns. Its more fun!! But its also a little more challenging at low speeds. I think for the first version to release, I will go with the pivot towards the front but possibly with the possibility of the back pivot.

Version v1.0 showed me that the idea of the flat cut parts bolted together with tubes worked. But the process of cutting and drilling everything was not scalable. Enter the waterjet cutter. I went to BigBlueSaw.com and uploaded the parts. I also made a few changes to make the cycle simpler with fewer parts. I also added back in a connection to bring the handlebars under the seat as in earlier versions.

The waterjet parts were not perfect but much easier to work with then raw material. In further versions widening the diameter of the holes by a small amount gave enough clearance to make assembly simple. The parts do require holes drilled and tapped in some of the parts sides for the pinch bolts, but in a few hours a complete cycle is ready.

Early 2017, I am riding the bellcycle around the neighborhood and occasionally from Harlem to the Flatiron. Most New Yorkers just ignore me. But for those bicyclists or people who look closely they yell some variant of "Where can I get that" or "What the f*&X is that."

My thoughts on manufacturing were

I could have visited a boutique local bicycle frame shop and had them TIG weld a custom frame or even perhaps build the entire cycle from my rough plans. This is expensive at probably a few hundred dollars per cycle.

I could try going overseas and working with existing bicycle manufacturers to make a more production ready prototype. This has other issues which I will address in another post.

Growing up in NYC I always wanted to build my own bike from scratch, frame and all. I had finally done that. But it wasn't easy. You can buy a kit and assemble a radio, computer etc from scratch, why not a bicycle? What would a cycle kit look like? Sure, you can buy a frame online and assemble, but what if you want to go further and assemble everything?

I downloaded Fusion360 from Autodesk and jumped in. Many modern motorcycles have an interesting construction of their front fork/ triple tree in which the forks are bolted between usually two aluminum members with the forks held via pinch bolts. As in below.

So I designed a version of the bellcycle in which the parts are made up of tubes( aluminum, steel, carbon fiber, whatever) are held together by a series of plates with pinch bolts.

Without building it, the benefits seemed to be

Mostly flat stock

Can be easily assembled with just a allen wrench

Should be cheaper at smaller volumes if there is no need for welding factories etc

I ordered the metal from onlinemetals.com. Used my hacksaw to cut out the shapes and a drill press with a variety of bits to drill out the required holes. Drilling a 30mm hole through a chunk of aluminum is not easy!! When building the design it became obvious the improvements in the design that were needed to reduce holes, angles, etc.

From there you can use the dxf file included in the project files or export a new DXF from the designs. You can use a waterjet cutter, plasma cutter, router, etc to cut the dxf file from .375" thick Aluminum 6061.

** Important. Depending on what machine you use you will have to take into account the accuracy and variation of the cutting. This may require some experimentation for each machine. A good example would be to cut a 1 inch hole in the material and then fit a 1 inch aluminum tube from the parts list into the hole. The hole should be .1" oversize for a nice clean fit.

Once you have your parts use a file to knockdown and sharp edges left over from cutting and your parts should look like this.

Spindle

You will also need a spindle to go through the front wheel. You can see in the designs above that the spindle is OD 17mm, 167mm Long and has standard square tapers.

Machine Shop -If you have access to a machine shop this will not be too difficult to make. Start with a 17mm Rod and cut four tapers in each end according to the CAD files.

Online Metal Shop- You can upload the design to a company such as eMachineShop.com and they can make you a spindle for around 100$ quantity 1.

Home Solution- You can purchase a 17mm OD Rod (http://alcobrametals.com/product/1SRM17A) and then using a file or grinder carefully remove enough material to create a 2 degree angle. See the CAD for precise dimensions.

Discussions

Become a member

this is very tempting for my commute (short ride to bus, easy to put on the bus), while avoiding some of the pitfalls of foldier bikes (un/foldtime), as long as it's not heavier than a regular bicycle. one of the ways to make that commute use-case even nicer might be to avoid a chain entirely -- chains being things that hit your pant legs and such. though perhaps now you have to worry about tire spokes...

oh, after a random find on this page, i see you've already thought of something like this: "However, in the future a inexpensive hub gear could be designed and produced which would simplify the cycle even further." i was going to mention this planetary gear hub is very nice looking (though expensive, $500!!):

but because of it's external interface, it would still require a chain. anyhoo, regarding any future plans for bellcycle v2 or v3, what are your thoughts/ideas for this hub gear? i think it could be a big selling point if marketed well :).

It looks like a fun toy, and congratulations for winning the Hackaday prize!

I ride a bike to commute 40 minutes each way every day. I need larger wheels to get me up to a faster speed.

I don't like folding bikes because the wheels are small, and they go at about half the speed. But I wish I could put my bike on a bus if it gets a puncture.

There is space for a wheelchair on a bus. And those wheels are the same size as a full-size bike's wheels. Would it be possible to build a full-size bike that can be converted into a wheelchair-size unit? Even if it took a few minutes with tools to disassemble the frame, I'd be interested to see what can be done.

Hello Peter. Yes you could simply extend the rear and front fork lengths to accomodate a full size (700c? 27inc?) wheel. Do you get a lot of flats? I used to get a lot of flats but then I switched to gatorskin tires and these tubes https://www.amazon.com/gp/product/B000BMUC2S they are really thick. After that I would go years between flats.

on a regular bike, it's nice to be able to stretch your leg out straight at the farthest pedal point -- and to be able to adjust the saddle height to do that. can the bellcycle adjust in this way? in the videos you still seem to have some bend in the knee.

Hello Lucas, There is a regular seat post clamp on the seat post and you can slide the seat post up and down in the "headset" tube. However, the adjustment is probably only 2-3 inches so not as much as you might get on a regular bike.

Someone else brought up that in my videos I dont fully extend my legs. I usually adjust it so I do. I will make sure in the next few videos to adjust the seat so I get full extension.

Hello Pete, riding in NYC i get lots of opportunities to test emergency stopping ( cab doors, etc) and its similar to a regular bike. The riders weight is pretty far back about equal distance between the two wheels. If you are leaning forward and really slam the brakes you can tip forward but I have done that on my regular bike also so I would say about equal.

https://www.instagram.com/p/BXOXY89DcG9 that is a video of me hitting a traffic partition with the rear wheels which is about as sudden a stop as you can get. You can see that the bike just stops and I go running forward.